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archive/design pattern/observer.cpp

@@ -0,0 +1,85 @@
+#include <iostream>
+#include <vector>
+using namespace std;
+
+class Observer
+{
+public:
+    virtual void sell(int) = 0;
+};
+class Subject
+{
+protected:
+    vector<Observer *> vec;
+
+public:
+    void add(Observer *o)
+    {
+        vec.push_back(o);
+    }
+    virtual void notify(int) = 0;
+};
+
+class DJIA : public Subject
+{
+public:
+    void notify(int price)
+    {
+        cout << "道琼斯发生了熔断,通知" << endl;
+        for (int i = 0; i < vec.size(); i++)
+        {
+            vec[i]->sell(price);
+        }
+    }
+};
+
+class SSE : public Subject
+{
+public:
+    void notify(int price)
+    {
+        cout << "上证突破3000点了,通知" << endl;
+        for (int i = 0; i < vec.size(); i++)
+        {
+            vec[i]->sell(price);
+        }
+    }
+};
+
+class Chives : public Observer
+{
+    string name;
+
+public:
+    Chives(string name)
+    {
+        this->name = name;
+    }
+    void sell(int price)
+    {
+        cout << name << ":买就行了,加仓干\n";
+    }
+};
+
+class Dalao : public Observer
+{
+public:
+    void sell(int price)
+    {
+        cout << "大佬:分析一下\n";
+    };
+};
+
+int main()
+{
+    Subject *a = new DJIA(), *b = new SSE();
+    Observer *c1 = new Chives("韭菜1"), *c2 = new Chives("韭菜2"), *dl = new Dalao();
+    a->add(c1);
+    a->add(dl);
+    b->add(c2);
+
+    a->notify(10000);
+    b->notify(3000);
+
+    return 0;
+}